What Do Lovers Whisper When the Sexometer's On? 'I'll Check My Chip, Dear'

A tale of modern romance: It's morning. He waits longingly. She pops a sensor at the end of a wire into her mouth, activates a device with a computer microchip inside and waits three minutes for a signal. Green means they can have sex that day without fear of pregnancy. Red means a cold shower.

The new device, officially the "intelligent thermometer" but inevitably nicknamed the sexometer, was invented by a team led by bioengineer Heinz Wolff at the British government-funded Clinical Research Centre near London. It's a computerized version of the rhythm technique, the only birth control method condoned by the Roman Catholic Church. Usually a woman charts her temperature daily to determine, as best she can, when she's fertile. Wolff's machine plots her temperature against her normal readings, then gives its surer judgment on safe days. A woman is most likely to be fertile the last three to four "red-light" days of her menstrual cycle but shouldn't assume sex early in her cycle is safe, Wolff warns: "That's called Vatican roulette."

There hasn't been a formal ruling yet on the sexometer from the Catholic clergy, though one priest in London, Father John Mahoney, says, "This method would bring peace of mind to people who have been using artificial birth control." However, Prof. Denis Hawkins, who teaches obstetrics at London's Hammersmith Hospital, doubts people will be dispassionate enough to use the device. "Sex doesn't work like a mechanical doll," he argues.

Wolff insists that, while a prolonged fever could fool the computer, the device could be as high as 99.9 percent accurate. This year 50 sexometers will be tested in Britain, but they won't be commercially available—at about $25 apiece—until 1982 because Wolff wants to conduct an educational campaign about their use first.

Born in Berlin, Wolff, 52, fled the Nazis in 1939 with his family and settled in Britain. He has worked since 1954 for the Medical Research Council. His current study is partially funded by the World Health Organization, which is seeking a simple, reliable means of population control. In the future, Wolff jokes, he might make a musical sexometer. It would play appropriate tunes—perhaps Too Close for Comfort on red-light days and Let's Do It (Let's Fall in Love) when the green flashes.